It is known to provide oil burners in which the fuel oil is supplied to a spinning rotary element, where the oil is atomized (i.e. vaporized, or reduced to the form of a spray). The atomized oil is mixed with air drawn into the burner, such mixing and ignition of the air/oil mixture taking place in the vicinity of the rotary element. Previously prepared oil burners of this type have, however, suffered from a number of disadvantages. For example, they have accomplished only incomplete combustion of the oil fuel. Whilst attempts have been made to design the parts of the apparatus so as to lead to recirculation of the combustible mixture through the combustion zone again after its first ignition, these have been only partially effective, and have lead to complications in structure of the apparatus. Further, problems have arisen with carbon build-up on the rotary element of the burner, necessitating frequent maintenance and cleaning for continued operation.